NEETBotanyCell - The Unit of Life
A student observes two cellular structures under an electron microscope. Structure X exhibits a 9+2 arrangement of microtubules, while Structure Y exhibits a 9+0 arrangement of microtubules forming a cartwheel pattern. Which of the following statements is true regarding Structure X and Structure Y?
Options
- AStructure X forms the basal body for Structure Y.
- BBoth Structure X and Structure Y are covered by a plasma membrane.
- CStructure X is covered by a plasma membrane, whereas Structure Y is a non-membrane bound organelle.
- DStructure Y represents the axoneme of a eukaryotic flagellum.
Correct answer
C. Structure X is covered by a plasma membrane, whereas Structure Y is a non-membrane bound organelle.
Step-by-step solution
Structure X, which has a 9+2 arrangement of microtubules, represents the core (axoneme) of a cilium or flagellum. Cilia and flagella are covered with a plasma membrane. Structure Y, which has a 9+0 arrangement of microtubules forming a cartwheel pattern, represents a centriole. Centrioles (found in centrosomes) are non-membrane bound organelles. Centrioles (Structure Y) form the basal body of cilia or flagella (Structure X), not the other way around. Therefore, Structure X is membrane-bound while Structure Y is non